[MattRix]

Opus is normally $5 per mtok, no idea why anyone would use /fast if they were at all concerned about price. ($5 is still pricy though tbh)

[krzyk]

Opus is $5 per mtok of input tokens, but $25 for output.

[MattRix]

Yes, but input is usually what people are talking about since that is the vast majority of token usage.

[krzyk]

I wouldn't call input a vast majority of token usage. In my experience output is 25%-33% of the cost.